Steel SUM24L · finish state
Steel SUM24L-TGP
Properties of the TGP condition, compared with the other SUM24L tempers.
Choose for pins and guide posts requiring h9/h11 diameter tolerance and Ra ≤ 0.4 µm directly from stock, since cold drawing plus grinding removes the need to turn the OD.
What is SUM24L-TGP?
SUM24L-TGP is SUM24L supplied in the TGP condition — choose for pins and guide posts requiring h9/h11 diameter tolerance and Ra ≤ 0.4 µm directly from stock, since cold drawing plus grinding removes the need to turn the OD. SUM24L-TGP has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 53% of steel grades. Elongation at break is 10% and the elastic modulus is 200 GPa (29 Msi). SUM24L-TGP has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 91% of steel grades. It melts at 1,420°C (2,588 °F). HR is the default condition FabDigit quotes; TGP is available on request or by drawing note.
Advantages
- Easy to machine — 98/100, better than 100% of steel grades
- Conducts heat well — 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High electrical conductivity — 10 % IACS, better than 82% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Difficult to weld — 10/100, worse than 99% of steel grades
- Limited ductility — 10%, worse than 91% of steel grades
- Limited service temperature — 280°C (536 °F), worse than 81% of steel grades
SUM24L-TGP properties
Typical room-temperature values for SUM24L-TGP — 9 properties are specific to this condition; the rest are grade-level values shared by every SUM24L temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
SUM24L-TGP has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 91% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical13
SUM24L-TGP has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 53% of steel grades. Elongation at break is 10% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
SUM24L-TGP is rated for continuous service to 280°C (536 °F). It conducts heat at 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
SUM24L-TGP conducts electricity at 10 % IACS, better than 82% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 87% of steel grades.
Sustainability4
Producing a kilogram of SUM24L-TGP takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 35%.
Manufacturability7
SUM24L-TGP's machinability is excellent (98/100, better than 100% of steel grades); weldability not recommended (10/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other SUM24L tempers and conditions
SUM24L is also supplied in 4 other conditions. The full side-by-side table is on the SUM24L overview.
- HRDefaultPick for large diameters or when further machining and heat treatment follow; it is the lowest-cost form but has the poorest dimensional tolerance and surface condition.235 MPa yield · 121 HB
- TGPChoose for pins and guide posts requiring h9/h11 diameter tolerance and Ra ≤ 0.4 µm directly from stock, since cold drawing plus grinding removes the need to turn the OD.420 MPa yield · 165 HB
- CDUse as the standard stock state for automatic lathe work: close diameter tolerance, smooth surface and the best chip breaking; most bar inventory is supplied as-drawn.415 MPa yield · 163 HB
- CRChoose for cold rolled flats, squares and special sections needing accurate flat dimensions; properties approach cold drawn at 395 MPa yield, with formability reduced to 32.395 MPa yield · 155 HB
- AnnealedPick for cold forming such as riveting, flanging and roll forming, or to remove cold-drawing residual stress; strength is lowest at 370 MPa tensile with 25 % elongation.220 MPa yield · 110 HB
Working with SUM24L-TGP
Is SUM24L easy to machine?
The reference grade for free cutting: run high-speed Swiss and turret lathes dry or with oil mist, with good chip breaking, long tool life and surface finish down to Ra 0.4 µm. Avoid it where the part is sensitive to low-toughness fracture.
Can SUM24L be welded?
Effectively unweldable: 0.3% sulfur and free lead cause severe hot cracking and lead fume hazard. Limit joining to small brazed areas on non-structural features or use structural adhesive.
Can SUM24L be formed, bent or molded?
Cold bending and flanging capability is poor because sulfide inclusions split along the rolling direction; if forming is required, use annealed stock and the largest possible bend radii. Knurling and thread rolling are practical.
What surface finishes work on SUM24L?
Black oxide, phosphate plus oil, zinc plating and nickel plating are the usual protective options. Remove all lead-bearing chip residue before plating, and check RoHS/REACH and export restrictions on the leaded composition.
SUM24L chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CJIS G4804 upper limit | ≤ 0.15 | 0.09 |
| Mn | 0.85 – 1.15 | 1 |
| Padded intentionally to improve machinability | 0.04 – 0.09 | 0.06 |
| SMnS inclusions break chips | 0.26 – 0.35 | 0.3 |
| Pbfree lead gives internal lubrication | 0.1 – 0.35 | 0.2 |
| Siusually not specified / low silicon | ≤ 0.1 | — |
| Fe | balance | — |
SUM24L-TGP — frequently asked
What is SUM24L-TGP used for?
SUM24L-TGP is typically used for screw machine parts, hydraulic and pneumatic fittings, threaded bushings and inserts, connector and sensor bodies, valve bodies and spool housings and light-duty pins and spacers. In short: leaded free-machining bar.
What is the yield strength of SUM24L-TGP?
SUM24L-TGP has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 53% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is SUM24L-TGP easy to machine?
Yes — machinability is rated excellent (98/100, better than 100% of steel grades). The reference grade for free cutting: run high-speed Swiss and turret lathes dry or with oil mist, with good chip breaking, long tool life and surface finish down to Ra 0.4 µm. Avoid it where the part is sensitive to low-toughness fracture.
Can SUM24L-TGP be welded?
Not readily — weldability is rated not recommended (10/100). Effectively unweldable: 0.3% sulfur and free lead cause severe hot cracking and lead fume hazard. Limit joining to small brazed areas on non-structural features or use structural adhesive.
What surface finishes work on SUM24L-TGP?
Black oxide, phosphate plus oil, zinc plating and nickel plating are the usual protective options. Remove all lead-bearing chip residue before plating, and check RoHS/REACH and export restrictions on the leaded composition.
Can SUM24L-TGP be formed, bent or molded?
Cold bending and flanging capability is poor because sulfide inclusions split along the rolling direction; if forming is required, use annealed stock and the largest possible bend radii. Knurling and thread rolling are practical.
What is the maximum service temperature of SUM24L-TGP?
SUM24L-TGP is rated for continuous use to about 280°C (536 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SUM24L-HR and SUM24L-TGP?
HR is the default condition — pick for large diameters or when further machining and heat treatment follow; it is the lowest-cost form but has the poorest dimensional tolerance and surface condition. TGP: choose for pins and guide posts requiring h9/h11 diameter tolerance and Ra ≤ 0.4 µm directly from stock, since cold drawing plus grinding removes the need to turn the OD. Yield strength is 235 MPa in HR versus 420 MPa in TGP.
Can FabDigit make parts in SUM24L-TGP?
Yes — SUM24L-TGP is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A108 / SAE J403 (12L14) — ASTM / SAE (2018)
- GB/T 8731 (Y15Pb) (2008)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Free-cutting steel bar datasheets (12L14 / SUM24L) — Nippon Steel / / Niagara LaSalle (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.